Automobiles and other vehicles provide a significant portion of transportation for commercial, government, and private entities. Vehicles, such as autonomous vehicles, drive on roadways that may experience structural decay and other problems that put vehicles, and their occupants, at risk. In some situations, a vehicle may be at risk for collision by another vehicle approaching from behind. For example, a first vehicle may suddenly stop or slow down to avoid an obstacle or stopping vehicles ahead of the first vehicle. In this situation, the first vehicle is at risk of being hit from behind by a second vehicle that doesn't stop fast enough. Early detection of a potential collision gives the vehicle time to take action to avoid or mitigate the collision.